From 08095e70783f1d8296f858d37a9e1878f5da0623 Mon Sep 17 00:00:00 2001 From: Keith Busch Date: Fri, 4 Mar 2016 13:15:17 -0700 Subject: [PATCH] NVMe: Create discard zero quirk white list The NVMe specification does not require discarded blocks return zeroes on read, but provides that behavior as a possibility. Some applications more efficiently use an SSD if reads on discarded blocks were deterministically zero, based on the "discard_zeroes_data" queue attribute. There is no specification defined way to determine device behavior on discarded blocks, so the driver always left the queue setting disabled. We can only know behavior based on individual device models, so this patch adds a flag to the NVMe "quirk" list that vendors may set if they know their controller works that way. The patch also sets the new flag for one such known device. Signed-off-by: Keith Busch Suggested-by: Artur Paszkiewicz Reviewed-by: Christoph Hellwig Reviewed-by: Martin K. Petersen Reviewed-by: Johannes Thumshirn Reviewed-by: Sagi Grimberg Signed-off-by: Jens Axboe --- drivers/nvme/host/core.c | 8 +++++++- drivers/nvme/host/nvme.h | 6 ++++++ drivers/nvme/host/pci.c | 3 ++- 3 files changed, 15 insertions(+), 2 deletions(-) diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index f08dccee8143..4304be00e556 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -582,8 +582,14 @@ static void nvme_init_integrity(struct nvme_ns *ns) static void nvme_config_discard(struct nvme_ns *ns) { + struct nvme_ctrl *ctrl = ns->ctrl; u32 logical_block_size = queue_logical_block_size(ns->queue); - ns->queue->limits.discard_zeroes_data = 0; + + if (ctrl->quirks & NVME_QUIRK_DISCARD_ZEROES) + ns->queue->limits.discard_zeroes_data = 1; + else + ns->queue->limits.discard_zeroes_data = 0; + ns->queue->limits.discard_alignment = logical_block_size; ns->queue->limits.discard_granularity = logical_block_size; blk_queue_max_discard_sectors(ns->queue, 0xffffffff); diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h index 9b71fa8c75e4..a402a0ebf471 100644 --- a/drivers/nvme/host/nvme.h +++ b/drivers/nvme/host/nvme.h @@ -59,6 +59,12 @@ enum nvme_quirks { * correctly. */ NVME_QUIRK_IDENTIFY_CNS = (1 << 1), + + /* + * The controller deterministically returns O's on reads to discarded + * logical blocks. + */ + NVME_QUIRK_DISCARD_ZEROES = (1 << 2), }; struct nvme_ctrl { diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c index d47b08783110..74514c767429 100644 --- a/drivers/nvme/host/pci.c +++ b/drivers/nvme/host/pci.c @@ -2130,7 +2130,8 @@ static const struct pci_error_handlers nvme_err_handler = { static const struct pci_device_id nvme_id_table[] = { { PCI_VDEVICE(INTEL, 0x0953), - .driver_data = NVME_QUIRK_STRIPE_SIZE, }, + .driver_data = NVME_QUIRK_STRIPE_SIZE | + NVME_QUIRK_DISCARD_ZEROES, }, { PCI_VDEVICE(INTEL, 0x5845), /* Qemu emulated controller */ .driver_data = NVME_QUIRK_IDENTIFY_CNS, }, { PCI_DEVICE_CLASS(PCI_CLASS_STORAGE_EXPRESS, 0xffffff) }, -- 2.39.5